kernel/trace/ring_buffer.c

446  * head_page == tail_page && head == tail then buffer is empty.
460 	struct buffer_page		*head_page;	/* read from head */
524 	struct buffer_page		*head_page;
1184  * Because the reader may move the head_page pointer, we can
1235 	head = cpu_buffer->head_page;
1332 	if (RB_WARN_ON(cpu_buffer, !cpu_buffer->head_page))
1340 	page = head = cpu_buffer->head_page;
1350 				cpu_buffer->head_page = page;
1626 	cpu_buffer->head_page
1628 	cpu_buffer->tail_page = cpu_buffer->commit_page = cpu_buffer->head_page;
1865 		cpu_buffer->head_page = list_entry(next_page,
1940 		struct list_head *head_page, *prev_page;
1947 		head_page = &hpage->list;
1948 		prev_page = head_page->prev;
1954 				     ((unsigned long)head_page | RB_PAGE_HEAD);
1967 			head_page->prev = last_page;
2263 	struct buffer_page *iter_head_page = iter->head_page;
2311 	iter->page_stamp = iter->read_stamp = iter->head_page->page->time_stamp;
2350 	if (iter->head_page == cpu_buffer->reader_page)
2351 		iter->head_page = rb_set_head_page(cpu_buffer);
2353 		rb_inc_page(&iter->head_page);
2355 	iter->page_stamp = iter->read_stamp = iter->head_page->page->time_stamp;
4335 	iter->head_page = cpu_buffer->reader_page;
4339 	iter->cache_reader_page = iter->head_page;
4347 		iter->read_stamp = iter->head_page->page->time_stamp;
4383 	struct buffer_page *head_page;
4392 	head_page = cpu_buffer->head_page;
4416 	return ((iter->head_page == commit_page && iter->head >= commit) ||
4417 		(iter->head_page == reader && commit_page == head_page &&
4418 		 head_page->read == commit &&
4593 	rb_inc_page(&cpu_buffer->head_page);
4693 	if (iter->next_event >= rb_page_size(iter->head_page)) {
4695 		if (iter->head_page == cpu_buffer->commit_page)
4824 	if (iter->head >= rb_page_size(iter->head_page)) {
4850 			*ts = rb_fix_abs_ts(*ts, iter->head_page->page->time_stamp);
5221 	cpu_buffer->head_page
5223 	rb_clear_buffer_page(cpu_buffer->head_page);
5228 	cpu_buffer->tail_page = cpu_buffer->head_page;
5229 	cpu_buffer->commit_page = cpu_buffer->head_page;
6017 		cpu_buffer->head_page
6019 		cpu_buffer->tail_page = cpu_buffer->commit_page = cpu_buffer->head_page;